This invention relates generally to valves and more particularly to an aseptic valve for use in food product processing and the like.
In the food processing field agricultural food products gathered from a farm are not immediately processed into a final form of processed food. These agricultural food products have seasonal characteristics and are harvested in large quantities. These food products are partially processed and are temporarily stored as primarily-processed food products and are then processed into final food products as they are withdrawn from storage.
An example is tomatoes which have seasonal characteristics and are harvested in large quantities. They are not immediately processed into final food products such as tomato sauce, tomato ketchup or the like. They are first primarily-processed and are stored as a puree or a paste. The primarily-processed food products are then processed into final processed food products as they are withdrawn from storage containers.
A most important aspect of the production of processed food products is to store the primarily-processed food products in a perfectly sterilized state. Storage of primarily-processed food products in a large storage tank is presently the most effective used method. When the primarily-processed food products are stored in a large storage tank the temperature must be kept as low as possible taking into consideration the possibility of deterioration and viscosity resistance thereof. In addition, much attention must be given to the microbiological contamination of the primarily-processed food products. The contamination of supply and discharge pipes connected to a large storage tank in which a primarily-processed product is stored, the contamination of a valve disc for restricting the supply and discharge of the primarily-processed food product and of the tank itself and accessory parts attached thereto, and the entry of microorganisms which may contaminate the product stored in the tank, must not take place, even if such contamination is extremely small.
Methods of and apparatus for storing primarily-processed food products in an aseptic manner have been disclosed in, for example, U.S. Pat. Nos. 3,871,824; 3,918,678; 3,918,942; 3,951,184; and 3,998,589 issued to Rechtsteiner et al. Among these patents, U.S. Pat. No. 3,918,678 entitled "Aseptic Bulk Material Storage System" is directed to an aseptic valve for use in storing primarily-processed agricultural products in a large tank under aseptic conditions.